ACPI: platform_profile: Add support for hidden choices

When two drivers don't support all the same profiles the legacy interface
only exports the common profiles.

This causes problems for cases where one driver uses low-power but another
uses quiet because the result is that neither is exported to sysfs.

To allow two drivers to disagree, add support for "hidden choices".
Hidden choices are platform profiles that a driver supports to be
compatible with the platform profile of another driver.

Fixes: 6888347 ("ACPI: platform_profile: Allow multiple handlers")
Reported-by: Antheas Kapenekakis <[email protected]>
Closes: https://lore.kernel.org/platform-driver-x86/[email protected]/T/#mc068042dd29df36c16c8af92664860fc4763974b
Signed-off-by: Mario Limonciello <[email protected]>
Tested-by: Antheas Kapenekakis <[email protected]>
Tested-by: Derek J. Clark <[email protected]>
Acked-by: Ilpo Järvinen <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Rafael J. Wysocki <[email protected]>

Author: superm1

drivers/acpi/platform_profile.c

@@ -21,9 +21,15 @@ struct platform_profile_handler {
 	struct device dev;
 	int minor;
 	unsigned long choices[BITS_TO_LONGS(PLATFORM_PROFILE_LAST)];
+	unsigned long hidden_choices[BITS_TO_LONGS(PLATFORM_PROFILE_LAST)];
 	const struct platform_profile_ops *ops;
 };
 
+struct aggregate_choices_data {
+	unsigned long aggregate[BITS_TO_LONGS(PLATFORM_PROFILE_LAST)];
+	int count;
+};
+
 static const char * const profile_names[] = {
 	[PLATFORM_PROFILE_LOW_POWER] = "low-power",
 	[PLATFORM_PROFILE_COOL] = "cool",
@@ -73,7 +79,7 @@ static int _store_class_profile(struct device *dev, void *data)
 
 	lockdep_assert_held(&profile_lock);
 	handler = to_pprof_handler(dev);
-	if (!test_bit(*bit, handler->choices))
+	if (!test_bit(*bit, handler->choices) && !test_bit(*bit, handler->hidden_choices))
 		return -EOPNOTSUPP;
 
 	return handler->ops->profile_set(dev, *bit);
@@ -239,21 +245,44 @@ static const struct class platform_profile_class = {
 /**
  * _aggregate_choices - Aggregate the available profile choices
  * @dev: The device
- * @data: The available profile choices
+ * @arg: struct aggregate_choices_data
  *
  * Return: 0 on success, -errno on failure
  */
-static int _aggregate_choices(struct device *dev, void *data)
+static int _aggregate_choices(struct device *dev, void *arg)
 {
+	unsigned long tmp[BITS_TO_LONGS(PLATFORM_PROFILE_LAST)];
+	struct aggregate_choices_data *data = arg;
 	struct platform_profile_handler *handler;
-	unsigned long *aggregate = data;
 
 	lockdep_assert_held(&profile_lock);
 	handler = to_pprof_handler(dev);
-	if (test_bit(PLATFORM_PROFILE_LAST, aggregate))
-		bitmap_copy(aggregate, handler->choices, PLATFORM_PROFILE_LAST);
+	bitmap_or(tmp, handler->choices, handler->hidden_choices, PLATFORM_PROFILE_LAST);
+	if (test_bit(PLATFORM_PROFILE_LAST, data->aggregate))
+		bitmap_copy(data->aggregate, tmp, PLATFORM_PROFILE_LAST);
 	else
-		bitmap_and(aggregate, handler->choices, aggregate, PLATFORM_PROFILE_LAST);
+		bitmap_and(data->aggregate, tmp, data->aggregate, PLATFORM_PROFILE_LAST);
+	data->count++;
+
+	return 0;
+}
+
+/**
+ * _remove_hidden_choices - Remove hidden choices from aggregate data
+ * @dev: The device
+ * @arg: struct aggregate_choices_data
+ *
+ * Return: 0 on success, -errno on failure
+ */
+static int _remove_hidden_choices(struct device *dev, void *arg)
+{
+	struct aggregate_choices_data *data = arg;
+	struct platform_profile_handler *handler;
+
+	lockdep_assert_held(&profile_lock);
+	handler = to_pprof_handler(dev);
+	bitmap_andnot(data->aggregate, handler->choices,
+		      handler->hidden_choices, PLATFORM_PROFILE_LAST);
 
 	return 0;
 }
@@ -270,22 +299,31 @@ static ssize_t platform_profile_choices_show(struct device *dev,
 					     struct device_attribute *attr,
 					     char *buf)
 {
-	unsigned long aggregate[BITS_TO_LONGS(PLATFORM_PROFILE_LAST)];
+	struct aggregate_choices_data data = {
+		.aggregate = { [0 ... BITS_TO_LONGS(PLATFORM_PROFILE_LAST) - 1] = ~0UL },
+		.count = 0,
+	};
 	int err;
 
-	set_bit(PLATFORM_PROFILE_LAST, aggregate);
+	set_bit(PLATFORM_PROFILE_LAST, data.aggregate);
 	scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &profile_lock) {
 		err = class_for_each_device(&platform_profile_class, NULL,
-					    aggregate, _aggregate_choices);
+					    &data, _aggregate_choices);
 		if (err)
 			return err;
+		if (data.count == 1) {
+			err = class_for_each_device(&platform_profile_class, NULL,
+						    &data, _remove_hidden_choices);
+			if (err)
+				return err;
+		}
 	}
 
 	/* no profile handler registered any more */
-	if (bitmap_empty(aggregate, PLATFORM_PROFILE_LAST))
+	if (bitmap_empty(data.aggregate, PLATFORM_PROFILE_LAST))
 		return -EINVAL;
 
-	return _commmon_choices_show(aggregate, buf);
+	return _commmon_choices_show(data.aggregate, buf);
 }
 
 /**
@@ -373,21 +411,24 @@ static ssize_t platform_profile_store(struct device *dev,
 				      struct device_attribute *attr,
 				      const char *buf, size_t count)
 {
-	unsigned long choices[BITS_TO_LONGS(PLATFORM_PROFILE_LAST)];
+	struct aggregate_choices_data data = {
+		.aggregate = { [0 ... BITS_TO_LONGS(PLATFORM_PROFILE_LAST) - 1] = ~0UL },
+		.count = 0,
+	};
 	int ret;
 	int i;
 
 	/* Scan for a matching profile */
 	i = sysfs_match_string(profile_names, buf);
 	if (i < 0 || i == PLATFORM_PROFILE_CUSTOM)
 		return -EINVAL;
-	set_bit(PLATFORM_PROFILE_LAST, choices);
+	set_bit(PLATFORM_PROFILE_LAST, data.aggregate);
 	scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &profile_lock) {
 		ret = class_for_each_device(&platform_profile_class, NULL,
-					    choices, _aggregate_choices);
+					    &data, _aggregate_choices);
 		if (ret)
 			return ret;
-		if (!test_bit(i, choices))
+		if (!test_bit(i, data.aggregate))
 			return -EOPNOTSUPP;
 
 		ret = class_for_each_device(&platform_profile_class, NULL, &i,
@@ -453,12 +494,15 @@ EXPORT_SYMBOL_GPL(platform_profile_notify);
  */
 int platform_profile_cycle(void)
 {
+	struct aggregate_choices_data data = {
+		.aggregate = { [0 ... BITS_TO_LONGS(PLATFORM_PROFILE_LAST) - 1] = ~0UL },
+		.count = 0,
+	};
 	enum platform_profile_option next = PLATFORM_PROFILE_LAST;
 	enum platform_profile_option profile = PLATFORM_PROFILE_LAST;
-	unsigned long choices[BITS_TO_LONGS(PLATFORM_PROFILE_LAST)];
 	int err;
 
-	set_bit(PLATFORM_PROFILE_LAST, choices);
+	set_bit(PLATFORM_PROFILE_LAST, data.aggregate);
 	scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &profile_lock) {
 		err = class_for_each_device(&platform_profile_class, NULL,
 					    &profile, _aggregate_profiles);
@@ -470,14 +514,14 @@ int platform_profile_cycle(void)
 			return -EINVAL;
 
 		err = class_for_each_device(&platform_profile_class, NULL,
-					    choices, _aggregate_choices);
+					    &data, _aggregate_choices);
 		if (err)
 			return err;
 
 		/* never iterate into a custom if all drivers supported it */
-		clear_bit(PLATFORM_PROFILE_CUSTOM, choices);
+		clear_bit(PLATFORM_PROFILE_CUSTOM, data.aggregate);
 
-		next = find_next_bit_wrap(choices,
+		next = find_next_bit_wrap(data.aggregate,
 					  PLATFORM_PROFILE_LAST,
 					  profile + 1);
 
@@ -532,6 +576,14 @@ struct device *platform_profile_register(struct device *dev, const char *name,
 		return ERR_PTR(-EINVAL);
 	}
 
+	if (ops->hidden_choices) {
+		err = ops->hidden_choices(drvdata, pprof->hidden_choices);
+		if (err) {
+			dev_err(dev, "platform_profile hidden_choices failed\n");
+			return ERR_PTR(err);
+		}
+	}
+
 	guard(mutex)(&profile_lock);
 
 	/* create class interface for individual handler */

include/linux/platform_profile.h

@@ -33,13 +33,16 @@ enum platform_profile_option {
  * @probe: Callback to setup choices available to the new class device. These
  *	   choices will only be enforced when setting a new profile, not when
  *	   getting the current one.
+ * @hidden_choices: Callback to setup choices that are not visible to the user
+ *		    but can be set by the driver.
  * @profile_get: Callback that will be called when showing the current platform
  *		 profile in sysfs.
  * @profile_set: Callback that will be called when storing a new platform
  *		 profile in sysfs.
  */
 struct platform_profile_ops {
 	int (*probe)(void *drvdata, unsigned long *choices);
+	int (*hidden_choices)(void *drvdata, unsigned long *choices);
 	int (*profile_get)(struct device *dev, enum platform_profile_option *profile);
 	int (*profile_set)(struct device *dev, enum platform_profile_option profile);
 };